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authorYang Shi <shy828301@gmail.com>2021-05-05 04:36:11 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2021-05-05 21:27:23 +0300
commit2bfd36374edd9ed7f2ebf66cacebedf7273901cb (patch)
tree4057a4164394a02a2ffa092fb152bb842eba5182 /mm/vmscan.c
parent8efb4b596df05f004e847d6bfadad3492b766ab3 (diff)
downloadlinux-2bfd36374edd9ed7f2ebf66cacebedf7273901cb.tar.xz
mm: vmscan: consolidate shrinker_maps handling code
The shrinker map management is not purely memcg specific, it is at the intersection between memory cgroup and shrinkers. It's allocation and assignment of a structure, and the only memcg bit is the map is being stored in a memcg structure. So move the shrinker_maps handling code into vmscan.c for tighter integration with shrinker code, and remove the "memcg_" prefix. There is no functional change. Link: https://lkml.kernel.org/r/20210311190845.9708-3-shy828301@gmail.com Signed-off-by: Yang Shi <shy828301@gmail.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Kirill Tkhai <ktkhai@virtuozzo.com> Acked-by: Roman Gushchin <guro@fb.com> Reviewed-by: Shakeel Butt <shakeelb@google.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/vmscan.c')
-rw-r--r--mm/vmscan.c132
1 files changed, 129 insertions, 3 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c
index d231af7cae06..bead5ae1e7e2 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -185,6 +185,132 @@ static LIST_HEAD(shrinker_list);
static DECLARE_RWSEM(shrinker_rwsem);
#ifdef CONFIG_MEMCG
+
+static int memcg_shrinker_map_size;
+static DEFINE_MUTEX(memcg_shrinker_map_mutex);
+
+static void free_shrinker_map_rcu(struct rcu_head *head)
+{
+ kvfree(container_of(head, struct memcg_shrinker_map, rcu));
+}
+
+static int expand_one_shrinker_map(struct mem_cgroup *memcg,
+ int size, int old_size)
+{
+ struct memcg_shrinker_map *new, *old;
+ struct mem_cgroup_per_node *pn;
+ int nid;
+
+ lockdep_assert_held(&memcg_shrinker_map_mutex);
+
+ for_each_node(nid) {
+ pn = memcg->nodeinfo[nid];
+ old = rcu_dereference_protected(pn->shrinker_map, true);
+ /* Not yet online memcg */
+ if (!old)
+ return 0;
+
+ new = kvmalloc_node(sizeof(*new) + size, GFP_KERNEL, nid);
+ if (!new)
+ return -ENOMEM;
+
+ /* Set all old bits, clear all new bits */
+ memset(new->map, (int)0xff, old_size);
+ memset((void *)new->map + old_size, 0, size - old_size);
+
+ rcu_assign_pointer(pn->shrinker_map, new);
+ call_rcu(&old->rcu, free_shrinker_map_rcu);
+ }
+
+ return 0;
+}
+
+void free_shrinker_maps(struct mem_cgroup *memcg)
+{
+ struct mem_cgroup_per_node *pn;
+ struct memcg_shrinker_map *map;
+ int nid;
+
+ if (mem_cgroup_is_root(memcg))
+ return;
+
+ for_each_node(nid) {
+ pn = memcg->nodeinfo[nid];
+ map = rcu_dereference_protected(pn->shrinker_map, true);
+ kvfree(map);
+ rcu_assign_pointer(pn->shrinker_map, NULL);
+ }
+}
+
+int alloc_shrinker_maps(struct mem_cgroup *memcg)
+{
+ struct memcg_shrinker_map *map;
+ int nid, size, ret = 0;
+
+ if (mem_cgroup_is_root(memcg))
+ return 0;
+
+ mutex_lock(&memcg_shrinker_map_mutex);
+ size = memcg_shrinker_map_size;
+ for_each_node(nid) {
+ map = kvzalloc_node(sizeof(*map) + size, GFP_KERNEL, nid);
+ if (!map) {
+ free_shrinker_maps(memcg);
+ ret = -ENOMEM;
+ break;
+ }
+ rcu_assign_pointer(memcg->nodeinfo[nid]->shrinker_map, map);
+ }
+ mutex_unlock(&memcg_shrinker_map_mutex);
+
+ return ret;
+}
+
+static int expand_shrinker_maps(int new_id)
+{
+ int size, old_size, ret = 0;
+ struct mem_cgroup *memcg;
+
+ size = DIV_ROUND_UP(new_id + 1, BITS_PER_LONG) * sizeof(unsigned long);
+ old_size = memcg_shrinker_map_size;
+ if (size <= old_size)
+ return 0;
+
+ mutex_lock(&memcg_shrinker_map_mutex);
+ if (!root_mem_cgroup)
+ goto unlock;
+
+ memcg = mem_cgroup_iter(NULL, NULL, NULL);
+ do {
+ if (mem_cgroup_is_root(memcg))
+ continue;
+ ret = expand_one_shrinker_map(memcg, size, old_size);
+ if (ret) {
+ mem_cgroup_iter_break(NULL, memcg);
+ goto unlock;
+ }
+ } while ((memcg = mem_cgroup_iter(NULL, memcg, NULL)) != NULL);
+unlock:
+ if (!ret)
+ memcg_shrinker_map_size = size;
+ mutex_unlock(&memcg_shrinker_map_mutex);
+ return ret;
+}
+
+void set_shrinker_bit(struct mem_cgroup *memcg, int nid, int shrinker_id)
+{
+ if (shrinker_id >= 0 && memcg && !mem_cgroup_is_root(memcg)) {
+ struct memcg_shrinker_map *map;
+
+ rcu_read_lock();
+ map = rcu_dereference(memcg->nodeinfo[nid]->shrinker_map);
+ /* Pairs with smp mb in shrink_slab() */
+ smp_mb__before_atomic();
+ set_bit(shrinker_id, map->map);
+ rcu_read_unlock();
+ }
+}
+
/*
* We allow subsystems to populate their shrinker-related
* LRU lists before register_shrinker_prepared() is called
@@ -212,7 +338,7 @@ static int prealloc_memcg_shrinker(struct shrinker *shrinker)
goto unlock;
if (id >= shrinker_nr_max) {
- if (memcg_expand_shrinker_maps(id)) {
+ if (expand_shrinker_maps(id)) {
idr_remove(&shrinker_idr, id);
goto unlock;
}
@@ -590,7 +716,7 @@ static unsigned long shrink_slab_memcg(gfp_t gfp_mask, int nid,
* case, we invoke the shrinker one more time and reset
* the bit if it reports that it is not empty anymore.
* The memory barrier here pairs with the barrier in
- * memcg_set_shrinker_bit():
+ * set_shrinker_bit():
*
* list_lru_add() shrink_slab_memcg()
* list_add_tail() clear_bit()
@@ -602,7 +728,7 @@ static unsigned long shrink_slab_memcg(gfp_t gfp_mask, int nid,
if (ret == SHRINK_EMPTY)
ret = 0;
else
- memcg_set_shrinker_bit(memcg, nid, i);
+ set_shrinker_bit(memcg, nid, i);
}
freed += ret;